Trans Fat and Twitter: Threats to Health and Wealth

The government warns of the dangers of a popular fat and a popular IPO. Also, labor-force participation falls to a generational low.

I'm from the government, and I'm here to help you." It's one of those lines that hard experience teaches us to treat skeptically, along with such classics as "the check is in the mail." As checks head toward extinction -- along with snail mail -- that old saw may fade from use, along with such quaint anachronisms as "dialing the phone." But government, if anything, is getting bigger than ever.

In the latest instance, the Food and Drug Administration last week sought to ban trans fats from...